1. Field of the Invention
The present invention relates to an Internet Protocol (i.e., “IP”) addressing technique, and more particularly, to a device for looking up an IP address using a ternary content addressable memory (i.e., “CAM”).
2. Description of the Related Art
These days, as Internet users are rapidly increasing and network traffic requiring a broadband, such as multimedia, is growing, the quality of Internet service has deteriorated remarkably. To cope with this problem, various attempts have been made in the art.
In an attempt to improve the routers to provide higher quality Internet service, improving packet throughput has been difficult. Specifically, there have been problems in the case of looking up an Internet protocol (i.e., “IP”) address in a router.
Exemplars in the art include publications of RFC (Request for comments) 1517, 1518, 1519 and 1520, a publication entitled A Longest Prefix Match Search Engine for Multi-gigabit IP Processing by Kobayashi, M., Murase, T., and Kuriyama, A., in IEEE International Conference on Communications, vol. 3, June 2000, pp. 1360-1364, U.S. Pat. No. 5,920,886 issued to Feldmeier on 6 Jul. 1999 for Accelerated Hierarchical Address Filtering and Translation Using Binary and Ternary CAMs, U.S. Pat. No. 6,081,440 issued to Washburn et al. on 27 Jun. 2000 for Ternary Content Addressable Memory (CAM) Having Fast Insertion and Deletion of Data Values, U.S. Pat. No. 6,237,061 issued to Srinivasan et al. on 22 May 2001 for Method for Longest Prefix Matching in a Content Addressable Memory, U.S. Pat. No. 6,252,872 issued to Tzeng on 26 Jun. 2001 for Data Packet Filter Using Contents Addressable Memory (CAM) and Method, U.S. Pat. No. 6,288,922 issued to Wong et al. on 11 Sep. 2001 for Structure and Method of an Encoded Ternary Content Addressable Memory (CAM) Cell for Low-power Compare Operation, U.S. Pat. No. 6,370,145 issued to Dally et al. on 9 Apr. 2002 for Internet Switch Router, U.S. Pat. No. 6,418,042 issued to Srinivasan et al. on 9 Jul. 2002 for Ternary Content Addressable Memory with Compare Operand Selected According to Mask Value, U.S. Pat. No. 6,401,130 issued to Cain for Auto Aggregation Method for IP Prefix/Length Pairs, U.S. Pat. No. 6,374,326 issued to Kansal et al. for Multiple Bank Cam Architecture and Method for Performing Concurrent Lookup Operations, U.S. Pat. No. 6,052,683 issued to Irwin for Address Lookup in Packet Data Networks, and U.S. Pat. No. 6,061,712 issued to Tzeng for Method for IP Routing Table Lookup.
I have found that the earlier art have failed to provide an improved apparatus for looking up Internet protocol addresses.